Surgical site infections (SSIs) are infections that occur after an invasive surgical procedure. A study conducted in Bangladesh found that 20.16% of 496 surgical patients developed wound infections. SSIs can be caused by exogenous sources like contaminated air or instruments, or endogenous sources such as the patient's own skin flora. Risk factors include patient characteristics like age, diabetes, and local factors like wound contamination. SSIs are classified as superficial incisional, deep incisional, or organ/space infections. Prevention strategies include proper patient preparation, sterile technique in the operating room, timely administration of prophylactic antibiotics, and postoperative wound management. SSIs significantly increase hospital costs and negatively impact patient outcomes.

1. SURGICAL SITE
INFECTION (SSI)
PRESENTED BY A.S. MARZAN AHMED
INTERN DOCTOR
SURGERY UNIT 1, SOMCH

2. What is SSIs?
 Surgical Site Infections (SSIs) are infections of the tissues,
organs, or spaces exposed by surgeons during performance of
an invasive procedure.

3. Prevalence of SSIs in a tertiary
hospital of Bangladesh (BSMMU)
Prospective data were collected on 496 surgical patients
admitted in the surgery department in BSMMU from January
2010 to June 2010. All preoperative risk factors were evaluated.
Patients operated were followed in the post operative period and
if any wound infecton noted, swab from the site of infection was
sent for culture and sensitivity and antibiotics were given
accordingly. Following 496 elective operations 20.16% patients
developed wound infection. Highest numbers of infection were
seen in the fifth decade with slight female preponderance.

4. Sources of SSIs
1. Exogenous Sources
a. Air current deposition of
contaminated particulates
b. Direct contact of micro-
organisms from contaminated
hands, instruments or implants
2. Endogenous Sources
a. Hematogenous seeding
from a pre-existing infection at
a remote site.
b. Patient’s own skin flora

5. Pathophysiology
Micro-organisms are normally prevented from causing infection in
tissues by
• mechanical: intact epithelium
• chemical: low gastric pH;
• humoral: antibodies, complement and opsonins;
• cellular: phagocytic cells, macrophages, polymorphonuclear
cells and killer lymphocytes.
It may be compromised by any comorbid condition of the patient,
surgical intervention and treatment leading to SSI.

6. Pathophysiology (cont.)

7. Classifications of SSIs
 Incisional SSIs
– Superficial
– Deep
 Organ/space SSIs

9. Percentage of SSIs in different types of
wounds
Wound Class Expected Infection
Rates
Examples of cases Management
Clean (class I) 1%-2% Hernia repair, breast
biopsy specimen
Primary closure
Clean/contaminated
(class II)
2.1%-9.5% Cholecystectomy,
elective GI surgery
(not colon)
Primary closure
Contaminated (class
III)
3.4%-13.2% Penetrating abdominal
trauma, large tissue
injury
Delayed primary
closure, or packed
open and allowed to
heal by secondary
intention
Dirty (class IV) 3.1%-12.8% Perforated
diverticulitis,
necrotizing soft tissue
infection
Packed open and
allowed to heal by
secondary intention

10. Risk Factors for Development of
Surgical Site Infection
 Patient factors
 Local factors
 Microbial factors

11. Patient factors
 Older age
 Immunosuppression
 Obesity
 Diabetes mellitus
 Chronic inflammatory process
 Malnutrition
 Smoking

12. Patient factors (cont.)
 Renal failure
 Peripheral vascular disease
 Anemia
 Radiation
 Chronic skin disease
 Carrier state (e.g., chronic Staphylococcus carriage)
 Recent operation

13. Local factors
 Open compared to laparoscopic surgery
 Poor skin preparation
 Contamination of instruments
 Inadequate antibiotic prophylaxis
 Prolonged procedure
 Local tissue necrosis
 Blood transfusion
 Hypoxia, hypothermia

14. Microbial factors
 Prolonged hospitalization (leading to nosocomial organisms)
 Toxin secretion
 Resistance to clearance (e.g., capsule formation)

15. Incisional SSIs
 Incisional SSIs occurred if a surgical wound drains purulent
materials or if the surgeon judges it to be infected and opens it.

16. Superficial incisional SSIs
 Infection occurs within 30 days after surgical procedure
 Involves only skin and subcutaneous tissue of the incision
 Patient has at least 1 of the following:
a. Purulent drainage from the superficial incision
b. Organism isolated from an aseptically-obtained culture of fluid
or tissue

17. Superficial incisional SSIs (cont.)
c. Superficial incision that is deliberately opened by a surgeon
and is culture positive or not cultured and patient has at least one
of the following signs or symptoms: pain or tenderness, localized
swelling, redness, heat
d. Diagnosis of superficial SSI by surgeon or attending physician

18. Deep Incisional SSIs
 Infection occurs within 30 days after the operation if no implant is left
in place or within 1 yr. if implant is in place and the infection appears
to be related to the operation.
 Involves deep soft tissues of the incision, e.g., fascial & muscle
layers
 Patient has at least 1 of the following:
a. Purulent drainage from deep incision
b. Deep incision spontaneously dehisces or opened by surgeon and
is culture positive or not cultured and fever >38 C, localized pain or
tenderness (Note: a culture negative finding does not meet this
criterion)

19. Deep Incisional SSIs (cont.)
c. Abscess or other evidence of infection found on direct exam,
during invasive procedure, by histopathologic exam or
imaging test
d. Diagnosis of deep SSI by surgeon or attending physician

20. Organ/space SSIs
 Examples:
‒ Intra abdominal absence
‒ Leakage from a gastro-intestinal anastomosis leading to postoperative
peritonitis.
‒ Infected pancreatic necrosis
 Organisms causing organ/space SSIs:
‒ Bacteroids spp.
‒ E.coli
‒ K.pneumoniae
‒ Enterococci
‒ Pseudomonas spp.

21. Diagnostic Work-up
1. Clinical presentation
 Spreading erythema of the skin around the incision line
 Local pain
 Local oedema
 Heat
 Pyrexia

22. Clinical presentation (cont.)
 Increased exudate /suppuration
 Abscess formation
 Lymphangitis
 Cellulitis
 Loss of function of a limb
 Septacaemia

23. Diagnostic Work-up (cont.)
2. Investigation
I. Microbiological studies
 Stop antibiotics 2-3 weeks before
 Specimen collection
 Gram stain or AFB stain
 Culture
II. Inflammatory markers
Inflammatory markers (CRP, ESR, WBC count) are high up to two
weeks after surgery.

24. Investigation (cont.)
III. Imaging Study
 Imaging plays an inferior role in early infection.
 Useful in delayed and late infections to assess the extent of
infection.
Includes
 Ultrasonography
 Computed Tomograhpy (CT)

25. TREATMENT

26. Treatment of incisional SSIs
 Effective therapy consists solely of incision and drainage
without the additional use of antibiotics. Antibiotic therapy is
reserved for patients in whom evidence of significant cellulitis is
present or who concurrently manifests a systemic inflammatory
response syndrome.
 The open wound is allowed to heal by secondary intention with
dressing being changed twice a day.

27. Treatments of organ/space SSIs
 Administration of an antibiotic to which the organism is
sensitive, often 14 to 21 days of therapy are required.
 Reset or repair the diseased organ debridement of necrotic
infected tissue and debris.
 In case of intra-abdominal abscess surgical re exploration and
drainage is done.

28. PEVENTION IS BETTER THAN CURE

29. Preoperative Shower/bathe either the day before surgery or the day of the surgery
Remove hair with electrical clippers if required. Do not use razors to remove hair
Patients and staff to wear specific theatre clothing, and remove nail polish and jewelry
Avoid routine MRSA nasal decontamination and bowel preparation
Use antibiotic prophylaxis for all but clean surgery with no prosthesis or implant, using local
policies
Do not use mechanical bowel preparation routinely
Intraoperative Decontaminate hands
Wear sterile gowns and double gloves if high risk of contamination
Prepare skin with antiseptic chlorhexidine/povidone-iodine preparation
Avoid diathermy for skin incisions
Avoid normothermia, perfusion, and aim for Hb saturation of 95%
Cover wounds with dressings
Do not use wound irrigation or intracavity lavage to reduce the risk of surgical site infection
Postoperative Change dressing aseptically
Clean wounds with sterile saline up to 48 hours, tap water after this
Involve tissue viability specialists for wound dressing on wound healing by secondary intention.
Use appropriate antibiotics for infected wounds
NICE guidance on preventing surgical site infection

30. Prophylactic antibiotic

31. Do Remember

32. Preoperative phase (antibiotic
prophylaxis)
 Prophylaxis is limited to the time prior to and during the
operative procedure.
 The first dose of prophylactic antibiotics are given intravenously
at the induction of anesthesia
 For regular surgery, a single dose of antibiotic is required
 For patients who undergo complex and prolonged procedures
in which the duration of the operation exceeds the serum drug
half-life should receive an additional dose or doses of
antimicrobial agent.

33. Preoperative phase (antibiotic
prophylaxis) (cont.)
 There is no evidence that administration of postoperative doses
of an antimicrobial agent provides additional benefit.
 Empiric therapy is given when the risk of a surgical infection is
high. This therapy should be limited to a short course of drug (3
to 5 days).
 De-escalation therapy is given based on patient response and
culture results.

34. Prophylactic use of antibiotics
1. Use antibiotic prophylaxis only when wound contamination is
expected or when operations on a contaminated site may lead
to bactaraemia. It is not required for clean- wound procedures
except:
a) When you insert an implant or vascular graft
b) In valvular heart disease to prevent infective endocarditis
c) During emergency surgery in a patient with pre existing or recently
active infection
d) If an infection would be very severe or have lifetime threatening
consequences.

35. Prophylactic use of antibiotics (cont.)
2. The choice of antibiotic prophylaxis is determined by the
surgical procedure itself. Operations potentially contaminated
by skin flora require prophylaxis against staphylococcal
infection with flucloxacillin 500 mg intravenously. Procedures
involving the bowel require co-amoxiclav or a cephalosporin
with metronidazole.

36. Measures WHO recommendation
Preoperative bathing Yes- either with plain soap or antimicrobial
Mupirocin ointment for Staph aureus infection Yes- for nasal carriers
Screening of ESBL colonization No recommendation made
Optimal timing for preoperative surgical antibiotic
prophylaxis
Should be within 120 minutes of surgical incision
considering half- life of antibiotic
Mechanical bowel preparation combined with the use of
oral antibiotics
Yes- in elective colorectal surgery
Hair removal Should only be removed with a clipper (not shaved)
Surgical site preparation Alcohol based antiseptic solution based on Chlorohexidine
Gluconate
Antimicrobial skin sealants (sterile film forming
cyanoacrylate based sealant)
Antimicrobial sealants should not be used after surgical
site skin preparation
Surgical hand preparation Either antimicrobial soap and or a suitable alcohol based
hand rub
WHO guideline 2016 for prevention of SSI for peri operative period

37. Enhance nutritional support (oral or enteral) For underweight patient undergoing major operation
Perioperative discontinuation of immunosuppressive
agents
Don’t stop immunosuppressive mediation
Perioperative oxygenation Patients with endotracheal intubation should receive an
80% fraction of inspired oxygen intraoperative and if
feasible 2-6 hours postoperatively
Maintain normal body temperature (normothermia) Warming devices recommended
Use of protocols for perioperative blood glucose control Yes- protocols for intensive perioperative blood glucose
control for diabetics and non- diabetics
No recommendation on optimal target glucose levels due
to lack of evidence
Maintenance of adequate circulating volume
control/normovolemia
Goal directed fluid therapy intraoperatively is
recommended

38. Drapes and gowns Sterile, disposable non- woven or sterile reusable woven
drapes and gowns
Plastic adhesive incise drapes are not recommended
Incisional wound irrigation prior to wound closure No recommendation made for irrigation with saline
Irrigation with aqueous Povidone Iodine particularly in
clean and clean contaminated wound should be
considered
Antibiotic incisional wound irrigation shouldn’t be used
Prophylactic negative pressure wound therapy Yes for risk wound
Use of surgical gloves No recommendation made on double gloving, change of
gloves during the operation or a specific type of gloves
made
Antimicrobial coated sutures Yes- Triclosan coated sutures
Laminar flow ventilation systems for operating room
ventilation
No- laminar airflow shouldn’t be used to reduce the risk of
SSI for patients undergoing total arthroplasty surgery
Surgical antibiotic prophylaxis prolongation after the
completion of the operation
No- antibiotic therapy shouldn’t be prolonged beyond the
operation
Advanced dressing, e.g alginates, hydrocolloids No- not recommended
Antimicrobial prophylaxis in the presence of a drain and
optimal timing for drain removal
Not recommended to prolong antibiotics in the presence
of a drain
No recommendation given on optima timing of a drain
removal

39. Why SSIs is significant
 SSI can double the length of time a patient stays in hospital and
thereby increase the costs. Main additional cost are related to
re-operation, extra nursing care and interventions and drug
treatment costs.
 Poor scars that are cosmetically unacceptable, such as those
that are spreading, hypertrophic or keloid, persistent pain and
itching restriction of movement, particularly when over joints,
and a significant impact on emotional wellbeing.

40. THANK YOU